New classes of Si-based photonic materials and device architectures via designer molecular routes

Ge/Sn-based group IV semiconductors with tunable band gaps across the wide IR range were synthesized using designer hydrides with tailored Si, Ge and Sn stoichiometries and structures. GeSn, SiGeSn, SiSn and SiGeSn/Ge heterostructures undergo indirect to direct band gap transitions via strain engineering and alloy composition tuning, providing the basis for integration of microelectronics with optical components into a single chip. SiGeSn systems also enable buffer layer technologies with unprecedented lattice and thermal matching capabilities for applications in monolithic integration of III–V semiconductors with Si electronics.